1. Field of the Invention
The invention relates to a writing instrument having a pressure mechanism that moves a writing element from a retracted position of rest into an advanced writing position, in which the writing element is retained against the writing pressure. From the advanced position the mechanism returns to the position of rest by means of spring pressure and displacement of a retention element, out of an engagement position with the instrument housing.
2. Brief Description of the Prior Art
In a known writing instrument of this type (DE-AS No. 1 294 850) the rear end of the writing element, which is in the form of a ball point refill, extends into a blind bore of a retention element on which the clip of the writing instrument is formed. The retention element has a lateral protrusion extending into an opening of the instrument housing, so that it retains the writing instrument in the writing position by means of interaction of its rear surface with the rear end of the opening. The position of rest of the writing instrument is defined by interaction of a surface located further forward with the rear end of the opening, thus preventing backward movement of the retention element and writing element out of the instrument housing. The writing and retention elements are under a rearward-acting spring pressure so they are pushed backward into the position of rest by a tilting of the clip when the protrusion is freed from the retaining engagement position with the opening.
Thus, in this known writing instrument the user can move the writing element between a forwardly displaced writing position and a retracted position of rest, as well as from the position of rest into the writing position by the respective displacement by hand of a retention element.